Sealing structure



p 9,1952 :F.LASSF RD 1,609,893

SEALING STRUCTURE Filed 'Jan. 18, 1950 1 QIAQVIn'IIIM I IN V EN T 0R.ff"! 6.746197% r1 Patented Sept. 9, 1952 SEALING STRUCTURE FredGlassford, Royal Oak, Mich., assignor to Chrysler Corporation, HighlandPark, Mich., a

corporation of Delaware Application January 18, 1950, Serial No. 139,218

14 Claims. 1

This invention relates to sealing structure and more particularly to animprovedsealing structure applicable to shock absorbin devices.

According to a feature of the present invention there is the provisionof a novel and efficient sealing means for a shock absorber of thedirect acting type whereby the seal is self-centering as re spects thepiston rod and escape of fiuid around the latter is prevented.

According to another feature there is provided a seal tending toadjusting itself relative to the piston rod whereby wear on the pistonrod due to reciprocal movement is even around its girth According to yetanother feature, a shock absorber is provided having a self-centeringpilot plug on the pressure tube for reception in the seal-containin endof the reservoir tube to produce at that end a positive and uniformspacing between the foregoing tubes.

According to a further feature, a shock absorber is provided in whichthe step in assembly of joining the reservoir tube cap to the reservoirtube may precede the step of the insertion of internal parts such as thepiston rod seal and pressure tube plu during final assembly; in thosedevices requiring an inverse order of precedence to the above, therelies a, greater likelihood of taking foreign matter internally of theshock absorber since the full step of joinin must in such instance bemade with the piston rod seal and/or pressure tube plug in placeinternally thus forming a pocket difficult thereafter to flush clean.

According to yet a further feature, there is provided a shock absorberhaving a pressure tube plug and pressure tube insertable from an end incommon as respects the reservoir tube such that the former two pressuremembers may be inserted as a sub-assembled unit; inasmuch as thepressure tube plug and pressure tube are by commercial practicepress-fitted together, in the present invention the press-fitting stepmay take place outside the reservoir tube altogether with full access tothe sub-assembler and the resulting sub-assembly then inserted in thereservoir tube through the same end of the latter.

According to still a further feature, a shock absorber is provided inwhich the pressure tube plug provides for positive and uniform spacingof the pressure tube with the reservoir tube at one end notwithstandingthe non-coincidence of the axes of the two tubes at the opposite end asdue to irregularities and non-uniformity of the base cap and base valveassembly. By orthodox construction the base cap and/or base valve serveto space the lower end of the reservoir tube radially relative to thepressure tube.

With the above mentioned and other features, objects and advantages inview, the invention consists of the novel construction and combinationof parts hereinafter described and illustrated in the accompanyingdrawing, it being understood that various changes in the form,proportion, arrangement, and details of construction such as will besuggested to one skilled in the art may be resorted to without departingfrom the spirit of the invention.

In the drawing:

Figure 1 is a longitudinal section of the improved device;

Figure 2 is a plastic view illustrative of a step of assembly of thedevice; and

Figure 3 illustrates a certain self-centering feature of the invention.

Detailed reference will now be made to the accompanying drawingillustrating an improved form of direct acting hydraulic shock absorberwherein loss of fluid through leakage and uneven wear around the pistonrod is substantially eliminated. In proceeding into the detaileddescription, it should be with the understanding that the invention maybe embodied in other structures than the one preferred for illustration.

In Figure 1, the shock absorbing device In to which the invention hasbeen applied, includes opposed mounting eyes 12 and M at the respec tiveends. Received in these mounting eyes are rubber-like or plasticbushings l6 and 18 which embrace parts 20 and 22 mounted respectively ontwo relatively movable members of the apparatus to which the shockabsorbing device is to be applied, a vehicle suspension being oneexample. The centrally located piston rod 23 has a reduced end 24providing a shoulder 26. Received on shoulder 26 is the end member 28 ofa dust shield 30 fabricated as by welding. The end member 28 is held inplace against shoulder 25 by the shock absorber eye l2, which isaffixed. alon a surface 32 to the reduced portion 24 of the piston rod.Welding 34 or other suitable bonding techmques may be employed. A cap 36is provided at its base with a rim 38 held by a suitable fluidtight bondat 40 to a tubular reservoir member 35. The bond 40 consists preferablyof resistance welding in the form of a butt welding operation but withinits broader aspects may be crimped and spun over. Cap 36 may assume ahemispherical shape and be provided with arcuate wall portions 42 whichdefine a central opening 44. Opening 44 is of a dimension to affordadeaeoasee 3 quate clearance for reciprocable movement of piston rod 23notwithstanding assembly misalignments. The arcuate walls i2 may beformed to present hemispher'cal arcuate surfaces 4% internally thereof.A rubber-like or synthetic fiuid seal 53 of a non-metallic preferably isreceived within cap 35 and formed laterally with complemental arcuatesurfaces 56 adapted to mate with surfaces as 'just mentioned. A centralopening 52 is provided in seal 58 for reception of the piston rod 23 ina sealingly slidable engagement. Opposed lateral surfaces 54 formed onseal 38 engage a seat member 55 formed with a central opening 58 whichprovides adequate clearance in a noninterfering relationship with pistonrod 23. The seat member 55 is provided with an annular flange 69 whichreceives a coil element 62 of a resilient member fi l which biases theseal 48 into operative position. The resilient means 5d, which may be acoil spring, seats inan annular recess 66 formed in a rod guide plug 68.The rod guide plug 58 has a central opening 70 serving as a bearing forguiding movement of piston rod 23. Surfaces 12 formed on the guide plug68 are complementally received by the'surfaces it of the arcuate wallportions 42 of the cap. One or more passages M formed in the peripheryof the rod guide plug serve to connect a fluid leakage collectingchamber T5 with the reservoir chamber of the shock absorber formed byreservoir member 35. radiating fins l8 defining interveningfoam-collecting chambers 36 from which any froth or emulsion is passedinto the fluid-collecting chamber IS in a preceding order to other shockabsorbing fiuid operating to leak through the hearing opening Iii.Surfaces 82 are received as by a press fit in the end 33 of a pressuretube 8 1 which carries the rod guide plug 68. A shoulder 85, undercut asat 88 on the rod guide plug, serves to seat the members 68 and 8dfixedly in place relative to one another.

Pressure tube 84 defines a working cylinder 9d operatively divided bythe shock absorber piston into a rebound chamber 92 and a jounce chamberSt. The piston as a whole is indicated at 86 to include a reducedportion 98 of the piston rod 23. Ashoulder IE8 is provided at one end ofthe reduced portionnoted, and a threaded portion I 82 at the other end,on which is threadably received a nut I8 providing a shoulder Hi5opposed to the shoulder Iiiii. Between the said two shoulders isdisposed a piston valve body I86 carrying the piston skirt W8. bearingagainst shoulder see is provided with one or more apertures III. Aspacer H2 is located adjacent washer Iii? and next in order is to beobserved a flexible spring member we having a plurality of radiatingfingers I29. Fingers 52E! cooperate with a check valve Il a providing ashiftable valving portion I22 having fluid passage ports one or more innumber I I8 located centrally thereof. The portion I22 01" valve Iiiserves to cover and close an annular depression I26 which is formed inthe body member I66 such as to communicate with passages I26 extendinggenerally longitudinally'oi the piston. Passages ltd, which may be oneor more in number, are formed about a circle oi radially greater extentthan another circle upon which are disposed one or more through passagesi23, also formed in the piston. An annular depression 433 is formed toprovide uniform discharge communication for the passages I28 andthereacross are provided valving parts 32, I 534 and a backing member Ii-B.

Rod guide plug 68 has one or more A washer I It 4 Valve member I32 mayhave one or more peripheral notches I36, and valving member I3 3 mayhave one or more peripheral notches I38. Backing member His is receivedin a spring retainer cup I42 presenting a central opening M 3 slidinglycooperating with a complementary cylindrical portion 146 formed on nutHM. Spring cup M2 is urged in place by one end of a resilient member 148which may be in the form of a coil spring. A shoulder 556 formed on nutits serves to seat the resilient member M8 at the opposite end thereof.

Reservoir member 35, which may be tubular, defines with the pressuretube 2 a reservoir I52 for the shock absorber fluid in which iscontained an anti-aeration member 551 shown by way of illustration as acoil spring. A base cap 65% has a flange portion E58 which is receivedin a counterbore IEil formed in the reservoir member In adjacency to thefiange portion IE8, the anti-aeration member E541 may be connected toone or both of base cup 5% and reservoir tube By suitable welding,bonding, or crimping as at I62, base cap I55 may be firmly afiixed inplace with flange portion [58' being located within thereservoir tube.The mounting eye it of the shock absorbing device is firmly affixed to;base cap I56 at Ib l as by welding or a suitable bonding. One or moreinwardly offsetportions 5% are formed in base cap Ibt thereby to defineintervening passage means as at 58 which lead into the reservoir chamberI52. A portion of the base valve assembly is provided with surfaces Iltwhich rest on the offset portions I and further surfaces i'i i adaptedto be received as by a pressfit engagement in the lower end 85 ofpressure tube The base valve body part Il2 has valving surfaces I'll;formed to define the entrance to a central opening I18. One or morenotches lad are provided in the body member I72 so'as to cause the valvesurfaces I15 to be interrupted by gaps at intervals as desired. Thenotches I32: provide a permanent opening permitting constantcommunication as between reservoir I52 and jounce chamber 9t. Receivedon lugs I82 formed on body part H2 is a biasing member 58 formed with aplurality of resilient'spring fingers I36 which engage a check valvepart I88. Valve part I88 has valving surfaces I9ii which cooperate withthe valving surfaces lie just described. Valving part 388 defines acentral opening B93 in which is received a relief valve it l. In one endof the relief valve will be observed a central bore I95 which connectswith a peripheral slot I88. It will be understood that when valving partW4 assumes a position displaced downwardly from that shown, the bore andslot I96 and we will serve to allow communication between the jouncechamber 9 3 and the passage means I33 leading into reservoir I52. Ashoulder 28%; formed on relief valve I94 engages in an upward positionof the valve the body part I88 adjacent an end of the central openinglea formed therein. A second shoulder formed on relief valve lad isindicated at 202 to engage a resilient member 2% which may be a coilspring serving to keep the valve in seated position. Valving part I88defines a cylindrical recess in its base defining a chamber assembly ofthe construction features just described. It is contemplated that as asub-assembly step the cap 36 will be transversely aligned and buttwelded adjacent rim portion 38 thereof to the reservoir tube 35 to formthe outer casing for the shock absorbing device. After the butt weldingstep is accomplished, a unitary structure will result having an opening44 of reduced size at one end and an entirely open counterbored end atI60. Inasmuch as the piston rod guide 68 and the pressure tube 84 may beintroduced, owing to the unique principles of construction involved,through the same end of the casing, it is possible as a furthersub-assembly step to press fit plug 68 into pressure tube 84 previous toany further assembly of the shock absorbing device. As the twosub-assemblies just mentioned are brought together, the complementarysurfaces I2 and 46 formed on the casing and the pressure tubesubassembly respectively serve to pilot the pressure tube assemblyinternally into place and to center it relative to the reservoir member35 at least in the region of cap 36. It is to be appreciated that if thebutt welding operation causes the rim 30 to fuse unevenly and to unitewith reservoir tube 35 such that the cap is slightly canted relative tothe reservoir tube, still since hemispherical surfaces are involved, thepilot surfaces I2 will nevertheless cause the axes of plug 68 and casing35 to be coincident. As the mating surfaces 46 and I2 approach oneanother the resilient member 54 will be compressed to urge the springseat 56 and seal 48 into self-centering disposition relative to thepiston rod. The direction of taper of the seat member 56 is shown asbeing opposite to the direction of convergence of the arcuate walls 42.It will be readily apparent that if the outer and inner tubes 35 and 64are not in coincidence at their lower end due to some assemblydifliculty with base cap I56 and the base valve, still the surfaces 46and I2 will allow movement at the opposite end of the tubes relative toone another such that the said opposite end will be self-centeringdespite any existing canting between the two tubes adjacent the basecap.

As respects Figure 3 of the drawing, a somewhat exaggerated view of ashock absorber 3 I appears in which the central axis of the base cap 212is disposed at a discernible angle to the central axis 210 of thepressure tube and piston rod. Such a possibility may be found to existby reason of the canting of the inner and outer tube relative to oneanother at their lower ends or by uneven butt welding between the cap236 and reservoir tube 235 the same as noted above, or perhaps acombination thereof. In any case since the central axis 212 of cap 236is canted, the piston rod will seek a position in the central opening250 of the base cap which relatively is slightly off center. The pistonrod seal 248 will tend to center itself relative to the path of motionof the piston rod by a slidingly tiltable shift transverse of the shockabsorber casing from what may be an initial position 248, which latterposition will be seen to be centralized relative to the canted cap 236.

For an understanding of the operation of the devices of Figures 1through 3, the stroke during which the shock absorber parts collapsewill be termed for convenience sake, the jounce stroke and the strokeduring which the shock absorber parts extend relative to one anotherwill be referred to as the rebound stroke. During jounce, piston 96 willmove downwardly in the cylinder and the dampingfluid will tend to movepast the piston through passages I24 and will unseat the valve portionI22, which acts as a checkvalve, and make its way through ports I I Iinto the, rebound chamber 92. Simultaneously, the volume of dampingfluid displaced by piston rod 23 will at slow speeds of jounce tend topass spring fingers I86 in the base valve, enter notches I into thecentral opening I18 of the base valve, and pass through passage meansI68 into, res ervoir I52. As higher jounce speeds transpire, thepressure in jounce chamber 94 will rise and cause relief valve I94 tounseat and allow additional fluid to pass through bore I96, slot I98,and into the central cylindrical passage 205 defined by check valve partI88. This additional fluid will then make its way into reservoir I52.

At the beginning of the rebound stroke the damping fluid will make itsway from the reservoir tending to be drawn through the base valve so astounseat the check valve part I88 and allow relatively free passage offluid between the valv ing surfaces I16 and I90. This fluid will thenpass into jounce chamber 94. The fluid trapped above the piston in therebound chamber 92 will pass through opening I I I of the top of thepiston and since check valve I22 will close, will then make its way pastspring fingers I20 and the openings II8 into passages I28. From theannular recess I30 formed in communication with passages I28, the fluidwill pass through the peripheral notches I36 and I38 formed in valvemembers I32 and I34 respectively. With higher speeds of rebound, theflow past the piston will be supplemented owing to the fact that thevalve parts I32, I34, and I40 wil be lifted from their seats incident torising fluid pressure resulting in compression of the resilient memberI48. After sufficient pressure is reached to lift. the valve off itsseat during rebound, the balance of the stroke may continue at arelatively constant resistive force. Any voids trapped in the reboundchamber during rebound stroke will tend to be collected first in theupper chambers 80 and passed out with leakage fluid into thefluid-collecting chamber 16 for eventual reentry into the reservoirthrough passage I4. Relative to emule sion in the reservoir, the fluidwill seek a lower level and the anti-aerating device will tend to keepthe froth or emulsion from the main body of fluid in the reservoir.

From a study of the subject matter just disclosed, it will readily beapparent that an improved shock absorbing device has been provided inwhich any uneven wear on the piston rod is precluded due to the factthat the piston rod seal is self-centering. It will be further apparentthat in event the outer and inner tubes 35 and 84 are not exactlycoincident at their lower ends still these tubes will be made coincidentat their upper ends by virtue of a ball joint or universal swivelingaction between the rod guide plug and the upper cap for the casing.

What is claimed is:

1. In a shock absorber, a casing having a tubular side wall and anarcuate end wall connected thereto having an end opening therein, aworking cylinder in the casing having a plug at one end provided with acentral opening and having surfaces engaging the walls of the casing inspaced relation to said end opening and forming a chamber between saidplug and said end opening, a flexible non-metallic packing in-saidchamber having an arcuate surface adapted to engage said arcuate endwall complementally in a tiltingly slidable relationship, said packinghaving an opening centrally of said arcuate pack-' ing surface, and aresilient element acting in said chamber between said plug and packingto urge said arcuate surface of the latter into engagement with saidarcuate end wall and resiliently permitting the aforesaid tilting byslidable movement of the packing to effect appropri ate registry withthe aforesaid openings.

2. In a shock absorber, a casing having a tu bular side wall and anarcuate end wall connected thereto having an end opening therein, aworking cylinder in the casing having a plug at one end provided with acentral opening and having an. arcuate surface engaging said arcuate endwall of the casing in spaced relation to said end opening and forming achamber between said plug and said end opening, a flexible non metallicpacking in said chamber having an arcuate surface adapted to engage saidarcuate end wall complementally in a tiltingly slidable relationship,said packing having an opening centrally of said arcuate packingsurface, and a resilient element acting in said chamber between saidplug and packing to urge said arcuate surface of the latter intoengagement with said arcuate end wall and resiliently permitting theaforesaid tilting by slidable movement of the packing to effectappropriate registry of the aforesaid openings.

3'. In a shock absorber, a tubular member having an end and alongitudinal axis, a cap including a substantially semi-spherical crownportion and a rim portion at the base thereof welded fluid tight to theend of the tubular member, said crown portion having an openingsubstantially concentric with the central axis of the cap, a workingcylinder in the tubular member having aplug at the end thereof adjacentthe welded end of said tubular member and formed with a central openingcoaxial with the working cylinder, said plug having surfacescomplementary to internal surface portions of said cap and universallyslidable therein to accommodate. centering of the axis of the centralopening of said plug with the axis of the tubular member notwithstandingmisalignment of the latter and the cen tral axis of the cap.

4. ma shock: absorber, atubular member having an end and a longitudinalaxis, a cap having a central axis and including a substantiallysemispherical crown portion and a rim portion at. the base thereofbutt-welded fluid tight tothe end of the tubular member in transverselyaligned.

continuation thereof, a working cylinder in the tubular. member having aplug, at the end thereof adjacent the butt-welded end of said tubularmember and formed with a central opening coaxial with the workingcylinder, said plug having surfaces complementary to internal surfaceportions of said cap and universally slidable therein to accommodatecentering of the axis of the central opening thereof with the axis ofthe tubular member notwithstanding misalignment of the latter withcentral axis of the cap owing to fabrication irregularities as due tobutt-weldlng' operations.

5. In a sealing'structure of the'character described, the combinationwith a tubular casing having a reduced end provided' at its extremitywith an opening and including converging arcuate internal surfaceportions, of a reciprocable shaft extending non-interferingly throughsaid opening into the casing, a. tapered spring seat in the casingsurrounding the shaft and surroun dedbysaid internal arcuate convergingsurface portions with its direction of taper opposite ,to the directionof convergence of said arcuate surface portions, a non-metallic sealingring interposed between said: spring seat and said converging arcuateinternal surfaces having an opening through which said shaft sealingly'extends and having. opposed faces adapted to fit complementally to saidspring seat and arcuate surface respectively, said spring seat having aflange projecting radially beyond said sealing ring, a. spring mountedin the casing in surrounding relation to the shaft and having a coilelement embraced by the projecting flange of the spring seat, saidspring acting in a direction to urge the complemental face of thesealing ring into engagement with the said internal arcuate surfaces andcooperating with the same to permit resilient centering of the sealingring relative to the path of motion of said reciprocable shaft.

6. In a sealing structure of the character described, the combinationwith a tubular casing having a reduced end provided at its extremitywith an opening and including arcuate annular internal surface portionsconverging toward said extremity opening with ever decreasing insidediameter, of a reciprocable shaft extending noninterferingly throughsaid opening into the casing, a spring seat in the casing surroundingthe shaft and surrounded by said internal annular arcuate surfaceportions, a pressure tube assembly having a plug at one end and beingprovided with surface presenting portions engaging internal surfaceportions of said casing at a region spaced from the end opening of thelatter, a nonrnetallic sealing ring spaced at all points from saidpressure tube assembly in a position connected between and engaging saidspring seat and said internal annular arcuate surfaces and having anopening through which said shaft sealingly extends, said internalannular arcuate surface portions presenting unobstructed inner surfacesof substantial lateral extent generally beyond the dimensions of thepiston rod seal and adapted to permit engaged sliding therealong of theseal toward and away from the pressure tube assembly spaced relativethereto, aspring mounted in the casing in surrounding relation to theshaft andhaving a coil elementembraced by the spring seat, saidspringacting in a direction to urge sealing ring intoengag-ement with,

the said internal annular arcuate surfaces of ever. decreasin insidediameter and-cooperating with the same to permit resilient. centering ofthe sealing ring relative to the path of motion of said reciprocableshaft.

7-. In a shock absorber, the combination with a reservoir memberincluding a tubular main body portion having a substantially constantinside diameter and an open end, and including a cap at the other end ofsaid main body portion pro- 7 vided with a piston-rod opening ofa lesserdimen sion than said constantinside diameter, said cap having annularwall portions of ever-decreasing inside diameter located between saidopening and said main body portion and said cap being fixed fluid tightto the other end of said main body portion, of a piston rod-sealintroducib'le through said open eno. of said main body portion forengagement with the inside of said annular wall portions adjacent thepiston rod opening, a'pressure cylinder provided at one end with arodguide plug having lateral engageable surfaces, said pressure cylinderand rod-guide plug having a smaller dimension'tha-n said constant insidediameter for accommodating their introduction through said open end ofsaid tubular body portion whereby the rodguide plug and pressurecylinder may be advanced into said reservoir member in assembledrelation to bring said lateral engageable surfaces into contact withsaid annular walls, said plug being spaced from said piston-rod openingand seal by contact of said engageable surfaces and said annular wallportions, and interposed resilient means acting between said seal androd-guide plug.

8. In a shock absorber, the combination with a reservoir memberincluding a tubular main body portion having a substantially constantinside diameter and an open end and including a cap at the other end ofsaid main body portion provided with a piston-rod opening of a lesserdimension than said constant inside diameter, said cap having curvedannular wall portions of ever decreasing inside diameter located betweensaid opening and said main body portion and said cap being fixedfluid-tight to the opposite end of said main body portion, of a pistonrod seal introducible through said open end of said main body portionfor engagement with the inside of said annular Wall portions adjacentthe piston rod opening, a pressure cylinder provided at one end with arod-guide having lateral engageable surfaces of complemental curvatureto said curved annular walls, said pressure cylinder and rod-guide plughaving a, smaller dimension than said constant inside diameter foraccommodating their introduction through said open end of said tubularbody portion whereby the rod-guide plug and pressure cylinder may beadvanced into said reservoir member in assembled relation and thelateral engageable surfaces be caused to contact said curved annularwalls, said plug being spaced from said pistonrod opening and seal bycontact of said engageable surfaces and said annular wall portions, andinterposed resilient means acting between said seal and rod-guide plug.

9. In a shock absorber of the fluid displacement type the combination ofa plurality of tubular members arranged to provide a working cylinderand a reservoir around said cylinder, a plug in an end of one of saidmembers for preventing direct communication between the working cylinderand reservoir having arcuate portions in swivel engagement with theother member for spacing said members at one end and accommodatingswivel movement of the tubular members while being maintained inoperative spaced relation by said plug, and means forming a fluidcollecting chamber in adjacency to the plug.

10. In a shock absorber of the fluid displacement type the combinationof a plurality of tubular members arranged to provide a working cylinderand a reservoir around said cylinder, a plug in an end of one of saidmembers for preventing direct communication between the working cylinderand reservoir and having arcuate portions in swivel engagement withanother said member for spacing said members at one end andaccommodating swivel movement of said members while being maintainind inoperative spaced relation by said plug, and means forming a fluidcollecting chamber in adjacency to the plug, said plug being formed withmeans providing for passage of fluid between said collecting chamber andreservoir.

11. In a shock absorber the combination of a plurality of tubularmembers arranged to provide a working cylinder and a reservoir aroundsaid cylinder, a plug mutually engaging and physically spacing saidmembers at one end and in interposition thereat to prevent directcommunication between the working cylinder and reservoir, means forminga fluid collecting chamber in adjacency tothe plug, said plug havingmeans associated therewith forming alball joint with one tubular memberpermitting. limited tilting movement of the other tubular membertherewith While being maintained in operative spacing by said plug, andpassage means at the ball joint providing communication between saidcollecting chamber and reservoir.

12. In a shock absorber of the direct acting type having a casing, thecombination of a transversely disposed plug, a plurality of tubularparts generally arranged on one side of the: plug to provide a workingcylinder and a reservoir around said cylinder, and means defining afluid collecting chamber on the other side of the plug having a pistonrod opening therein spaced from said plug and of a lesser dimension,said means including walls extending from the opening generallyoutwardly and in a direction axially toward the plug for engagement withthe latter, and a piston rod seal of a predeterminedly greater dimensionthan said piston rod opening, said walls presenting unobstructed innersurfaces of lateral extent generally beyond the dimensions of saidpiston rod seal and adapted to permit engaged sliding therealong of theseal in transverse movement of the latter relative to the plug andcasing.

13. In a shock absorber of the direct acting type, the combination of atransversely disposed plug, a plurality of tubular parts generallyarranged on one side of the plug to provide a working cylinder and areservoir around said cylinder, means defining a fluid collectingchamber on the other side of the plug having a piston rod opening inspacing to the plug and of a lesser dimension, walls extending from theopening generally outwardly and in a direction axially toward the plugto a point of engagement with the latter, a piston rod seal of apredeterminedly greater dimension than said piston rod opening, andresilient means acting between the seal and plug, said walls presentingunobstructed inner surfaces of substantial lateral extent beyond thedimensions of said piston rod seal and being adapted to permit engagedsliding therealong of the seal in transverse movement of the latterrelative to the plug, and passage means in the periphery of said plugradially beyond said resilient means providing for passage of fluidbetween said fluid collecting chamber and reservoir.

14-. In a shock absorber, the combination with a reservoir memberincluding a tubular main body portion having a substantially constantinside diameter and an open end, and including a cap at the opposite endof said main body portion provided with a piston-rod opening of a lesserdimension than said constant inside diameter, said cap having annularwall portions of ever decreasing inside diameter located between saidopening and said main body portion and said cap being joined fluid-tightto the opposite end of said main body portion, and a piston rod sealintroducible through said open end of said main body portion forengagement with the inside of said annular wall portions adjacent thepiston rod opening, of a sub-assembly constituted by a pressure cylinderand a rod-guide plug provided with engageable surfaces some of which areadapted to be press-fit into reception in the r 11 12 pressure cylinderduring fabrication of said subassembly to form an integrated unit, said'pres- R N S CITED Sure cylinderand rod'guide plug having a smaller Thefollowing references are of record in the dimension than said constantinside diameter fil of this t; for accommodating introduction of the in-5 teg-rated sub-assembly through the open end of UNITED STATES PATENTSsaid tubular body portion whereby the sub-as- Number Name 7 Date semblymay be advanced into said reservoir mem- 2,431,210 Funkhouser pt- 6,1949 her .to bring other said plug engageable surfaces into contact withsaid annular wall portions. 10

FRED GLASSFORD.

